人为源二次有机气溶胶来自人为活动排放的挥发性有机物的大气氧化，在我国细颗粒物污染和气溶胶的气候效应中具有重要作用。人为源二次有机气溶胶的生成过程与机理尚不明确，特别对夜间NO3自由基氧化挥发性有机物在二次有机气溶胶生成和老化中的作用了解还很欠缺，亟需开展相关研究以评估其对气溶胶浓度的贡献和其气候环境效应。本研究拟针对NO3与典型人为源挥发性有机物及其降解产物反应生成的二次有机气溶胶开展实验室模拟研究。在分子水平上表征气相和颗粒相产物，定量气溶胶产率，并表征气溶胶的重要理化特性成云活性和光学性质。研究气溶胶老化与NO3在老化中的作用，包括环境条件和昼夜循环对气溶胶化学组成和理化性质的影响。同时开展相关的外场观测，综合实验室研究与外场观测回答夜间人为源二次有机气溶胶的来源和生成机制，为进一步在模式模拟中评估二次有机气溶胶的气候环境影响提供重要基础参数。

Anthropogenic secondary organic aerosol (SOA), formed by the oxidation of anthropogenic volatile organic compounds (VOCs), not only contributes a large fraction to the total PM2.5 mass concentration in China but also plays an important role in the climatic impact of aerosols. Compared with the anthropogenic SOA formation from the oxidation by OH radical during the daytime, the role of SOA formation during nighttime especially from the oxidation by NO3 radical is far from being clear. We propose to investigate the SOA formation from the oxidation by NO3 of anthropogenic VOCs and their degradation products in laboratory studies. We plan to determine the reaction products in both the gas-phase and particle-phase on the molecular level, quantify the SOA yield, and characterize cloud condensation nuclei activity and optical properties, two important physicochemical properties for the impact of aerosol on climate and the environment. Moreover, we will investigate the aging of SOA regarding the influence of environmental conditions and diurnal cycling on chemical composition and physicochemical properties of SOA as well as the role of NO3 in SOA aging. Furthermore, we will perform field studies regarding the role of NO3 radical in anthropogenic SOA formation. By integrating laboratory and field studies, this project will help understand the source of atmospheric SOA and the mechanism of its formation and provide important parameters to assess the impact of anthropogenic SOA on climate and the environment.